Referencing/Triggering One UDF from Another UDF

When referencing one UDF from another UDF use the $[Filename.Fieldname] technique descried in the Formatted Search manual and not the number technique. The number technique (like...$[$4.0.0] (for the Vendor/Customer Number on the screen)) works when you press Shift + F2, but the values cannot be automatically triggered from other UDFs.

The requirement was to have two UDFs on a marketing document (i.e., Purchase Order) and have the user select the first UDF using the Shift + F2 technique and then the second field would be automatically populated with a value determined by a query, that used the value from the first UDF.

When we used the $[$Fieldname.0.0] method, the value in the second UDF field would not automatically populate. After a little research, we found a "note" that indicated the $[filename.fieldname] technique should be used.

$[filename.U_fieldname]

This method worked perfectly. The only problem with this technique is that a separate query will need to be used for each marketing document. 

For instance, this was used on the Purchase Order screen and the reference was $[OPOR.U_Fieldname]. But if I wanted to use the same query on the Sales Order screen, I would need to create a separate query just for that screen $[ORDR.U_Fieldname].